Opponents will offer changes that seem reasonable but are lethal

They are officially known as reservations, but lawmakers call them "killer amendments." Attached to a treaty by the Senate, they require the President to renegotiate certain provisions. Although Reagan is expected to have little trouble getting the two-thirds majority needed to ratify the INF accord, such likely opponents of the treaty as North Carolina's Jesse Helms and Wyoming's Malcolm Wallop may aim to scuttle it by mustering a majority in favor of amendments that sound reasonable but would prove lethal.

Defenders will try to protect the pact by making sure that any refinements are expressed in the form of "declarations" or...